Method of and apparatus for slitting and expanding strip iron



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l T. WUPPERMANN 'METHOD OF AND APPARATUS FOR SLlTTING AND EXPANDING STRIP IRON Filed Jan. 20. 1925 Sheng-Sheet 1 fawn ...Mmmm www.- a

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T. WUPPE'RMANN METHOD QF AND AP'ARATUS FOR SLITTING AND -EXPNDING STRIP IRON Filed Jan.' 2o, 1925 2 Shouts-Shoot z Patented Aug. 25, 1925.

UNITED STATES THEODOR WUPPERMANN, OF SCHLEBUSCH-IVIANFORT, NEAR COLOGNE, GERMANY.

METHOD OF AND APPARATUS FOR SLITTING- ANI) EXPANDING- STRIP IRON.

Application filed January To all 'whom t may concern:

Be it known that I, THEoDoR VUrrE-R- MANN, a citizen of Germany, residing at Schlebusch-ll/Ianfort, near Cologne, in the State of Prussia, Germany, have invented certain new and useful Improvements in the Method of and Apparatus for Slitting and Expanding Strip Iron; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable' others skilled in the art to which it appertains to makel and use the same.

My invention relates to a method of, and apparatus for, slitting and expanding stripiron, and more particularly for the treatment of strip-iron by making alternate incisions from opposite edges of the strip, so that the incised strip can be expanded. The incisions are made by means of cooperating pairs of knives borne severally by an anvil and by a reciprocatory head. as hitherto practiced has been attended with the disadvantage that the incised strip of iron clings to the anvil and must be detached therefrom by some device which pushes it away from the anvil. In the practice of the present invention such de vices for pushing the slitted strip iron out of the spacesrbetween the knives of the anvil are not required. To this end the knives are given inclined flanks, so that the feeding action causes the material between the knives to slide out over these fianks and to escape.

Where the slitting is performed solely by means of knives shaped according to the incisions to be made, there is a very considerable strain on the material near the ends of the incisions, and the pressure required for making the cuts is high. According to the present invention this defect is remedied by perforating the strip iron before the incisions are made at the points where the incisions are terminate. Such perforations have the further advantage that they distribute the strain imposed on the material when under expansion. It has been found that in expanding strips which have been incised only, the strips are liable to be torn, but if the incisions terminate in rounded apertures made by perforations, the bending is distributed over the curved edge, and there is no risk of tearing.

Performing the slitting process in two This method 2o, 1925. serial No. 3,686.

stages, first perforating and then cutting, affords the possibility of introducing another important improvement. As ordinarily formed, the incisions from opposite edges of the strip overlap at their inner ends. As the incisions are close together, and the knives are only short distances apart, there can be only very small clearances between the knives, and the spaces between are soon filled with the scale from the iron, and with oil. To improve matters in this regard, the perforations made before the incisions, may be extended to the centre line of the strip, so that the incisions themselves need not overlap and the knives need" only extend to the centre. The distance between consecutive knives is consequently doubled. There is a corresponding increase of space between the knives, to receive scale and oil.

Another improvement included in the method consists in this, that the coacting pairs of cutters do not have parallel cutting edges to engage the work simultaneously, from end to end of the cut, but are inclined to each other at a small angle, so that the cut is made progressively from end to end, in the manner of a shearing out.

In the drawings the method is illustrated, with two examples of slitting apparatus for performing it.

Fig. l, is a View in longitudinal section, showing diagrammatically the work-engaging parts of the machine.

Fig. 2, is a plan view of the anvil, and in Fig. 2 the plane of section of Fig. 1 is indicated by the line l-l.

Fig. 3, is a view in elevation, showing the assembly of knives borne by the head. The point of view is at right angles, to that of Fig. l.

Fig. A, is a plan View of the strip, showing both stages of the slitting process.

Fig. 5, is a plan view of the second example of the anvil.

Fig. 6, is a plan view of a strip cut with the anvil shown in Fig. 5, both stages of the operation being presented.

Fig. 7, is a view in side elevation of a machine organized for service.

In the example shown in Figs. l to l the slitting device comprises a stationary anvil a in which several knives ZJ are set side by side in two rows which at their inner ends overlap. As best shown in Fig. 2, the

knives are of angular shape, in plan with obtuse angles w. The bodies of the knives are at their inner ends so cut away that they interdigitate closely with each other. Adjacent the cutting edge each knife presents a narrow upper surface c and forward of surface c (that is to say, nearer the source from which the material advances) an inclined flank al. The direction of feed is indicated in Fig. 2 by an arrow ai. The anvil knives coact with correspondingly shaped knives c borne by reciprocable head f. In front of the knives b, considered with reference to the direction of the strip movement, the anvil a has perforations g alternating with each other on opposite sides. Corresponding with these holes the head has punches L. The positions of the holes g and punches 7L are such that the incisions made by the knives form continuations of the punched holes, as shown in Fig. fl.

'In consequence of the angular shape of the knives, and the fact that the cutting edges extend transversely over the middle regions of the strip, but obliquely at the marginsv the strand cut by each successive pair of knives is narrower at the edge and wider at the middle of the strip; but, since the incisi-ons from opposite edges overlap, the wider medial portion of each strand is slit in two by the incision from the opposite edge. Thus throughout the length of the finished and expanded article the width is approximately uniform.

Above the anvil there is a plate c with a large aperture l@ for the passage of the knives e, and with holes Z for the punches 7L. This plate and the anvil a. define the path 'm for the advance of the iron strip. Fig. 1 shows the plate lifted.

The operation is as follows:

The iron strip is introduced at the left, Fig. l, into the space m and is fed forward by feed device j), step by step, through predetermined intervals, in proper coordination with reciprocation of head f. The strip is first given a series of staggered holes n (Fig. 4) by the descent of the head Then the head is lifted and the strip is fed forwards so that the holes a register with the inner ends of the cutting edges of the knives. The following descent of the head f makes angular incisions 0 joined to the holes n. At the same time fresh holes n are made by the punch .7b. By the act of making the incisions 0 the metal is forced between the knives and remains there when the head f is lifted. When the iron strip is fed forwards by the feed device p, the strands of metal which have been forced down between the knives slide up the inclined iianks d, so that the iron strip is detached from the anvil knives without other means, solely by the feed device.

The holes n are preferably rounded.

IVhen the strip is expanded the roundness of the edges of these holes prevents tearing, a tearing which might occur if the incisions terminated sharply. Moreover, the presence of the holes has the effect of reducing the strain necessary to complete the incisions and to force the strands down into the spaces between the knives b, under the action of the head.

In making the incisions it has been found of advantage not to make the cut simultaneously throughout its entire length, but to proceed in the manner of shearing, gradually from one end to the other. This is of particular importance in the present case), because if the whole incision were made at once, there would be relatively great concentration of stress at the inner end of the slit7 and relativelyT great distortion there, and consequent weakness. But if the cutting be performed progressively from the outer edge inward5 the stress exerted upon the metal at the end of the slit is less. The metal is, therefore, not weakened at the critical part by the cutting.

For the purpose of this method of cutting, the meeting edges of the companion knives Z) and e are not parallel with each other` but are adapted to overlap further at the outer edges of the strip. It has been f found of advantage to confine the inclination to the knives e of the head f, so that the cutting edges of the staggered assembly of knives e are inclined in relation to each other as shown in Fig. 8.

In the example shown in Figs. 1 to 4 the cutting edges of the successive knives o and e extend inwards so far that they overlap. The knife edges are accordingly very close together, as the iron strip must by the knives be cut into very narrow transverse strands. Hence the spaces between the knives in the anvil are inconveniently narrow and may become clogged with scale and oil. To effect enlargement of these spaces the holes g1 in the example according to Figs. 5 and 6, extend to the centre line of the anvil, and the punches b-orne by the head are correspondingly shaped and arranged, and the knives b1 of the anvil, and the knives of the head j also extend only to the centre. As best sho-wn by comparison of Fig. 5 with Fig. 2 the distance between successive cutting edges is thus doubled. Assuming the flanks d to have the same inclination as in Fig. 2, the doubling of the distance between successive knife edges doubles the depth of the channels g between the knife edges, and therefore quadruples the capacity of these channels. Consequently it takes much longer for the angular spaces or channels g to become filled with dirt, and cleaning of the anvil is only required at longer intervals. In actual practice the holes g1 and the corresponding punches borne by the head will eXtend somewhat beyond the centre line oi the anvil, it this can be done witho-ut undue weakening of the material.

In the drawings only a small number of knives t) e and of punches g z, is shown. The number is in tact much greater. The number which can be used depends on the power available and the accuracy of the feed device.

`In the example shown in Fig. 7, the press comprises a trame r provided with a bed r1, and guide ways r2, a head s reciprocating in said guide ways and' adapted to be operated from a ily wheel s1, a feeding apparatus comprising rollers p, pawl and ratchet mechanisms p1, a rod p2 carrying the pawls of the said pawl and ratchet mechanisms, a pinion p3 and a rack p4 engaging the saine and adapted to be operated 'from the liy wheel s by a link p5, uprights t having a drum 251 rotatably mounted thereon, and uprights 'w adapted to have a rod al rotatably mounted thereon. The iron-strip is coiled on the. drum t1 and taken therefrom by the feed rollers p, passed between anvil a and plate z', and after being cut is coiled on the rod al. Upon the downward stroke of the head the iron-strip is slit in the manner described.

I claim:

l. rlhe method herein described of slitting a blank of sheet metal in preparation for expansion which consists in punching a hole through the web oif the sheet at a point remote from the edge and then slitting the web between the punched hole and the edge of the sheet.

2. The method herein described of slitting a blank of sheet metal in preparation for expansion which consists in punching a hole through the web of the sheet at a point remote from the edge, and then forming a shear cut progressively from the edge to the previously punched hole.

3. rIhe method herein described ot slitting a strip of sheet metal in preparation for expansion which consists in pertorating the strip with a plurality of perforations eX- tending in two parallel rows throughout the length of the strip, and shearing the strip in two series of cuts extending from the two edges to the perforations or the more remote row.

4. Apparatus for making transverse incisions in strip iron, including cooperating knife carriers, each carrying a plurality of knives arranged in parallelism, the knives of one carrier being provided on one side with inclined Hanks, and means for `feeding material tothe knife-equipped carriers from that side on which the knives of one of the carriers are as aforesaid inclined.

5. In apparatus for making transverse incisions in strip iron, the combination of means for perforating a strip of iron, means for advancing the perforated strip, and means for slitting the advanced strip from its edge to the perforation previously formed through it.

6. In apparatus for making transverse incisions in strip iron, the combination of cooperating carriers equipped with cooperating means for punching holes in strip iron and with cooperating knives adapted to make incisions in the said strip iron from its edges to holes previously punched through it, and means for feeding strip iron from hole punching position to a position in which the cooperating knives in their action cut slits from the edges to and joining with the previously cut holes.

7. Apparatus for making transverse incisions in strip iron, comprising means for making two series of holes in said strip iron oppositely arranged with respect to the midline of the strip, cooperating knife carriers located at the rear ot said means and having knives disposed in parallelism and adapted to cut incisions in a strip from its opposite margins to the holes of the more remote series, and means for feeding strip iron to successive positions for being acted upon by said hole-making means and by said knifeequipped carriers.

8. Apparatus for making transverse incisions in strip iron, comprising means for making two series of elongated staggered holes in said strip iron, oppositely arranged with respect to the mid-line of the strip, cooperating kniie-carriers located at the rear of said means and having knives disposed in parallelism and adapted to cut incisions from the opposite margins of the strip to the holes of the more remote series, and means for feeding strip iron to successive positions for being acted upon by said holemaking means and by said knife-equipped carriers.

9. Apparatus for slitting strip iron comprising means for perforating a strip in two series of perforations, oppositely arranged with respect to, but extending to, the midline of the strip, and means operating in sequence upon the means last named for cutting in the strip incisions extending from its opposite edges to the perforations of the more remote series.

TIIEODUR WUPPERMANN. 

